Costs and Difficulties of Interstellar ‘Messaging’ and the Need for International Debate on Potential Risks


J. Billingham et al. (2014), JBIS67, pp.17-23

Refcode: 2014.67.17
Keywords: METI, SETI, Beacons, Microwave, Interstellar flight, Active SETI, Contact, SKA, Arecibo

We advocate international consultations on societal and technical issues to address the risk of Messaging to Extraterrestrial Intelligence (METI) transmissions, and a moratorium on future transmissions until such issues are resolved. Instead, we recommend continuing to conduct SETI by listening, with no innate risk, while using powerful new search systems to give a better total probability of detection of beacons and messages than METI for the same cost, and with no need for a long obligatory wait for a response. Realistically, beacons are costly. In light of recent work on the economics of contact by radio, we offer alternatives to the current standard methods of SETI searches. METI transmissions to date are faint and very unlikely to be detected, even by nearby stars. We show that historical leakage from Earth has been undetectable for Earth-scale receiver systems. Future space microwave and laser power systems will likely be more detectable.